a) Field of the Invention
It is very common in rural locations to not have access to municipal utility services including potable water. Many times the water loads required by farms or dairies are such that the municipal services can be overburdened and consequently the dairy or farm may be required to obtain its own water. Generally the farms turn to on-site groundwater or surface water. On-site groundwater is usually un-potable and depending on the geographic location may have soluble iron or manganese due to the lack of dissolved oxygen content.
As is generally known in the art, iron and manganese are common elements widely distributed in nature. In the absence of oxygen, both of these elements are soluble in water. Both elements may form compounds with other soluble elements and can pollute water making it undesirable for human use. An aeration process will help to remove the compounds. The soluble forms of iron and manganese are in the plus two valence oxidation state. Upon contact with oxygen, or any other oxidizing agents, both the ferrous iron and manganese are oxidized to higher valences, forming new ionic complexes which are not soluble to any appreciable extent. Therefore, with the addition of oxygen to the compound, the iron and manganese may be removed as a precipitate after aeration.
In addition to aeration of the water converting the ferrous iron into a precipitate, chemical oxidants such as potassium permanganate can also be used. These chemical oxidants may sometimes be used in connection with an aeration process to increase processing speed.
Iron particularly poses problems including taste, staining, and accumulation within the pipes themselves. Iron will generally cause a reddish-brown staining of laundry, porcelain, dishes, utensils, teeth and even glassware. Further, the iron will over time settle out and buildup deposits in pipelines, pressure tanks, water heaters, and water softeners. Thus there are associated increases in energy costs and maintenance costs for removal of the iron deposits. In dairies the iron content will directly contaminate the cows and limit milk output.
To remove the soluble iron from the water an oxidation and filtration process is used. Filtering systems of this sort are generally comprised of two separate categories, the actual filtration process through which the water is cleaned and the backwashing operation through which the filter is cleaned. These operations are equally important in the overall filtration process. The most common practice for filtration is to use gravity filtration in a downward mode, but several other modes of operation are possible including up-flow, by-flow, and pressure or vacuum filtration.
During the filtration process, the water is injected with oxygen and the soluble iron content oxidizes. The oxidized water is then filtered through a filter media, generally either by using a greensand glauconite (for gravity flow modes) or, a buoyant manufactured filter media (used in up-flow modes).
In either case, the filter media will accumulate large amounts of insoluble iron content and the buildup must be removed by backwashing.
The backwashing process must be performed on a regular basis, such as every other day or biweekly depending upon the size of the operation.
With proper backwashing, the filtration process will successfully remove approximately 90% to 95% of the soluble iron content out of the source water. The filtered water is then treated to remove the remaining 5% to 10% of the soluble iron content.
To initiate backwashing, many of the filtration systems utilize a siphoning process to initiate the backwashing. The siphoning system is generally an automated process. The siphoning process requires constant servicing and adjustments.
When the pipes themselves are fully operable and not clogged with iron deposits, the automatic hydraulic siphoning system works well. But, after continuous use the pipe components tend to accumulate the iron content and consequently, reduced flow capacity and additional weight on the pipes themselves throws the siphoning system off-balance. Thus, continuous maintenance and servicing is generally required. This constant servicing can pose a hardship on the rural farms and dairies which are operating under tight financial constraints as well as posing logistical maintenance and servicing problems.
In summary, an oxidation/filtration/backwash system to remove soluble iron or manganese content from source groundwater utilizing an improved backwashing system as well as an assembly of interchangeable and self serviceable components is strongly needed.
b) Background Art
Generally the most common practice for filtration is the gravity filtration in a downward mode, but several other modes of operation are possible including up-flow, by-flow, and pressure or vacuum filtration. Listed below are various filtration devices with emphasis on back flushing.
U.S. Pat. No. 6,187,178 (Lecornu et al.) shows a filter with several back flow means including a siphon. There is an air bleed included which insures the siphon being broken at the proper point.
U.S. Pat. No. 6,063,269 (Miller et al.) shows a filter in a hydraulic system in which a portion of the fluid in the return line, is drawn by Venturi, to the filter line.
U.S. Pat. No. 5,705,054 (Hyrsky) provides a filtered water in-take in which water flows out through pipe. If intake is blocked, flow through siphon tubs brings water in through intake. There is a tube which can be used for siphon control.
U.S. Pat. No. 4,537,687 (Piper) discusses a filter which is cleaned by back flushing. This device shows a reverse siphon started by the application of a section port to initiate a backflow siphon flow in tube.
U.S. Pat. No. 4,317,733 (Xhomnneux) shows a filter with a body and a backflow washing means including a siphon tube. The siphon tube causes the flow of fluid to go backwards. The siphon starts when filter is clogged and the fluid in the chamber reaches a particular level.
U.S. Pat. No. 4,229,292 (Mori et al) discloses a regenerating column which is provided with a flushing siphon that starts when the flushing fluid reaches the desired level. The regeneration operation is started by an operator rather than being an automatic means.
U.S. Pat. No. 3,841,485 (Malkin) shows in a siphon system which has back pressure increases a siphon is developed through a pipe which draws fluid through pipes to draw water through the filter element. There is a siphon breaker tube provided to stop the back flow.
U.S. Pat. No. 3,825,120 (Takahashi) shows a system which includes pump means for moving the fluid being handled. In addition to the pumps there is a siphon pipe means which passes fluid to container.
U.S. Pat. No. 3,549,012 (Mackrle) shows a system in which under cleaning conditions a siphon starts when fluid in it reaches the proper level and air control valves are closed. The suction developed by the siphon is applied to a second siphon to clear an upper section.
U.S. Pat. No. 3,502,212 (Ueda) provides a siphon tube which is filled by liquid as the filter clogs. There are also air flow and feeding means that controls the start and end of the cleaning cycle. When the cleaning cycle is started a siphon liquid flowing draws both liquid and filtered material to a drain.
U.S. Pat. No. 3,342,334 (Soriente et al.) show a filter system in which during the cleaning operation a valve is opened and flushing fluid flows down a pipe. U.S. Pat. No. 3,111,486 (Soriente) shows a back flow system in which liquid is delivered by a tube. When the filter is blocked fluid accumulates so that it reaches a point high enough to flow into a siphon and passes out of the filter system drawing the blocking material with it.
U.S. Pat. No. 2,879,891 (Beohner et al.) shows a filter which is provided with a siphon tube that fills when the back pressure caused by filter blockage, and the position of the air control means allow it to fill. When the siphon tube fills it draws fluid backwards through tubes and backwards through the filter materials and removes it.
U.S. Pat. No. 1,119,008 (Gibson) shows a water filtering system in which there is a pipe loop “L”, that appear to serve as a back flow cleaning siphon when valves are set for back washing. The control is in part a function of automatic float or flow control valves.
U.S. Pat. No. 630,988 (Reisert) shows a back flow system in which as the pressure increases liquid flows up pipe “l”, and down inner pipe “s”, so that a siphon is established.
Ukranian UA 411 (Dmitriyevich) discloses an oxidation/filtration apparatus where as the filtering medium muds the filter loss increases. The water level providing positive flow reaches a maximum height and primes a siphon to initiate rinsing of the filter medium.